Aircraft nacelle structures for turbine engines typically include composite structures which provide significant weight advantages to heavier metal materials. The composite structures may comprise, for example, a composite back skin and a composite top skin with a core material sandwiched in between. A thermal protection system may be coupled to the composite back skin via a plurality of attachment features. The thermal protection system may insulate the composite back skin from high temperatures in the engine, and may provide protection to the composite structure from thermal damage, such as delamination of the composite structure. However, the thermal protection system may obscure direct access to the composite back skin and make it difficult to detect damage in the composite back skin using conventional inspection techniques. Typically, the thermal protection system needs to be removed in order to inspect the composite back skin for any thermal or structural damage. However, removing and reinstalling the thermal protection system is time consuming and may result in damage to the thermal protection system or the composite structures. There is a need for methods to inspect the structural integrity of composite structures configured with thermal protection blankets without having to remove the thermal protection blankets or without direct access to the composite structure, and for methods that more objectively detect and measure damage through means other than direct contact with a composite structure.